/*
 * Copyright (C) 2011 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.dx.io.instructions;

/**
 * Base implementation of {@link CodeCursor}.
 */
public abstract class BaseCodeCursor implements CodeCursor {

	/** base address map */
	private final AddressMap baseAddressMap;

	/** next index within {@link #array} to read from or write to */
	private int cursor;

	/**
	 * Constructs an instance.
	 */
	public BaseCodeCursor() {
		this.baseAddressMap = new AddressMap();
		this.cursor = 0;
	}

	/** @inheritDoc */
	public final int cursor() {
		return cursor;
	}

	/** @inheritDoc */
	public final int baseAddressForCursor() {
		int mapped = baseAddressMap.get(cursor);
		return (mapped >= 0) ? mapped : cursor;
	}

	/** @inheritDoc */
	public final void setBaseAddress(int targetAddress, int baseAddress) {
		baseAddressMap.put(targetAddress, baseAddress);
	}

	/**
	 * Advance the cursor by the indicated amount.
	 */
	protected final void advance(int amount) {
		cursor += amount;
	}
}
